Structural, Mössbauer spectroscopy and magnetic study of Co1-xCdxFe2O4 ferrite synthesized by glycol-thermal method

The Cd2+ substituted Co1-xFe2O4 with concentrations of (0 <= x <= 0.7) nano ferrites were synthesized using the glycol-thermal method. X-ray diffraction (XRD) and Fourier-transformed infrared (FT-IR) spectroscopy confirmed the structural formation and nanocrystalline structure of spinel ferrites. Samples possess a cubic spinel lattice structure with crystallite sizes varying between 5.1 nm and 15.5 nm. Transmission electron microscopy (TEM) revealed fine particles which are nearly spherical in shape. The Fe-57 M & ouml;ssbauer spectral studies showed an ordered magnetic spin state for x <= 0.5 which transforms to a paramagnetic phase for x >= 0.6 due to the weakening of super-exchange interactions. The saturation magnetization (M-S) was the highest at x = 0 with a value of 73.3 emu/g and fluctuated between 44.3 emu/g and 19.8 emu/g after the addition of non-magnetic Cd2+ ions. The field dependence of dM/dH curves reveals the finite size effect which leads to the frustration in magnetic moments.